New research conducted by University of Iowa biologist David Soll and colleagues, and published in PLoS Biology sheds new light on the nature of biofilms that are often found on medical devices.
Items such as artificial hip joints, dentures, catheters and other man made devices placed inside the body, provide a potential breeding ground for complex communities of microorganisms.
Many of these organisms have proved resistant to both the human immune system and treatment with antibiotics and other medication. In fact about 90% of pathogens colonizing humans make a pathogenic biofilm that white blood cells, antibodies and even anti fungal agents cannot easily cross.
While previous research sounded logical and showed that a particular pathogen would form its own associated biofilm, Soll and colleagues discovered that the fungal pathogen Candida albicans makes two kinds of biofilm.
Whilst the two biofilms of Candida albicans are similar, Soll has shown how one of the layers, around 10% of the colony, consists of sexually active organisms that form a layer supportive to mating.
Most of the colonizing cells form a biofilm which cannot be penetrated and is resistant to any kind of attack, but are not actively reproducing, however, the sexually active layer is permeable and far less resistant to eradication. Soll said:
“Having two outwardly similar, but functionally different, biofilms provides us with one means of finding out what makes the pathogenic biofilm resistant to all challenges, and the sexual biofilm non-resistant. Whatever that difference is will represent a major target for future drug discovery.”
Thus Soll and colleagues, postulate that studying the differences between the two layers, the sexual “mating” layer and the impermeable asexual “resistant” layer, ought to provide an avenue and focus for future research. This will lead to new drugs that can combat the challenge of removing biofilms, found forming on medical devices that are inside the body for long periods of time.
Rupert Wingate